This format, commonly called binary-coded decimal format, represents numeric data items in radix 10, but with each digit of the value held in only one half of one computer character, as described in Table 1 below. The sign is held in a separate trailing digit (half-character) position; that is, at the right-hand or least significant end of the item.
Any unused half bytes are set to zero.
Table 1. COMPUTATIONAL-3 Digit Representation
| Digit Value |
Digit Representation in Hexadecimal |
| Left Half-Character (odd digit) |
Right Half-Character (even digit) |
| 0 |
x"00" |
x"00" |
| 1 |
x"10" |
x"01" |
| 2 |
x"20" |
x"02" |
| 3 |
x"30" |
x"03" |
| 4 |
x"40" |
x"04" |
| 5 |
x"50" |
x"05" |
| 6 |
x"60" |
x"06" |
| 7 |
x"70" |
x"07" |
| 8 |
x"80" |
x"08" |
| 9 |
x"90" |
x"09" |
Note: Count even and odd starting from the right.
Table 2 shows the sign digit used for COMPUTATIONAL-3; storage requirements for this format depend only on the number of "9s" in the PICTURE clause of the data item as shown in Table 3.
Table 2. COMPUTATIONAL-3 Sign Digit Representation
| Sign Convention in the PICTURE Clause |
Sign of Data Item Value |
Sign Half-character, in Hexadecimal |
| Unsigned |
n/a |
x"0F" |
| Signed |
+ |
x"0C" |
| Signed |
- |
x"0D" |
Table 3. Numeric Data Storage for the COMP(UTATIONAL)-3 or PACKED-DECIMAL PICTURE Clause.
| Bytes Required |
Number of Digits (Signed or Unsigned) |
| 1 |
1 |
| 2 |
2-3 |
| 3 |
4-5 |
| 4 |
6-7 |
| 5 |
8-9 |
| 6 |
10-11 |
| 7 |
12-13 |
| 8 |
14-15 |
| 9 |
16-17 |
| 10 |
18-19 |
| 11 |
20-21 |
| 12 |
22-23 |
| 13 |
24-25 |
| 14 |
26-27 |
| 15 |
28-29 |
| 16 |
30-31 |
| 17 |
32-33 |
| 18 |
34-35 |
| 19 |
36-37 |
| 20 |
38 |
Example:
- For COMPUTATIONAL-3 and PICTURE 9999, the number +1234 would be stored as follows:
where F represents the non-printing plus sign.
- For COMPUTATIONAL-3 and PICTURE S9999, the number + 1234 would be stored as follows:
where C represents the plus sign.
- For COMPUTATIONAL-3 and PICTURE S9999, the number -1234 would be stored as follows:
where D represents the minus sign.
The SYNCHRONIZED clause (with or without the LEFT or RIGHT phrase) has no effect on COMPUTATIONAL-3 data declarations.
